Aggron is one of the Pokémon that define crippling overspecialization, with its high defense, good attack, and low everything else. Aggron's poor special defense means it can't take special attacks, and his poor typing gives him a x4 weakness to the ever common ground and fighting moves, making its physical defense a moot point. It has a niche in the form of recoilless Head Smashes and the ability to try to sweep by setting up using Rock Polish, but this wasn't enough to make it have use in OU. However, Aggron is one of the Pokémon to get a mega evolution, and it's a great one. It loses its rock-typing, gets increased special defense, gains the ability filter, and its defense goes through the roof. Not only that, but its attack goes up to a great base 140. All of this combined makes Mega Aggron is a defensive behemoth, tanking physical hits like they're nothing and hitting back hard.

With a Rock Polish up, Aggron becomes blisteringly fast, outrunning most unscarfed Pokémon. It's high defense means it can find plenty of opportunities to set up. Iron Head is your STAB, Earthquake is great coverage, and the third move is another coverage option. Head Smash is a must if you're using regular Aggron, while Mega Aggron would prefer Stone Edge or Fire Punch. Autotomize can be used, though it will weaken Heavy Slam if you're using it.

A standard RestTalk set. Iron Head or Heavy Slam for damage, Curse as your boosting move, and the obvious Rest and Sleep Talk for a semi-decent recovery option. Dragon Tail or Roar can be used if you'd prefer phazing over boosting.

With max investment, Aggron gets the most terrifying physical defense in the game, allowing it to tank almost any physical hit with ease. The first two slots are your STAB and coverage, while the last two slots depend on what you want Aggron to do for you and your team, with your choices of either more coverage or more support. The attack EVs can be put into HP if you want to be able to tank even the hardest hitting moves, such as Close Combat from Terakion.

Checks and Counters

Aggron's biggest problem is its mediocre special defense and low speed. It will go down pretty quickly against Pokémon like Hydreigon, Heatran, and Megazard Y, all of which outspeed it. In addition, residual damage will work wonders against it, as Aggron has no reliable recovery. Burn almost completely shuts Aggron down, as it neuters its attack, leaving it unable to do much, and the burn damage will take its toll on Aggron's bulk. Wish and Heal Bell support are greatly appreciated for Aggron as a result.

More sets will be added later. Feel free to post any ideas for sets you have, or comment on the sets listed here.

Hey, remember that time the pokemon with amazing defense and HP got it's SpD shored up to good enough amounts, lost a crippling defensive typing for an acceptable one, and gained an amazing defensive ability? Pepperidge Farm Aggron remembers. Sereously, a full stalling Mega Aggron is a SEREOUS defensive threat, and I will not accept anyone trying to tell me otherwise. I don't CARE if it relies on Restalk for recovery, it has the ability TO WAIT THE REST OUT and not be threatened (and Suicune has gotten around that in the past, hasn't he?)

What about something tried in the past? An Autotomize set for MegaAggron may be good. MegaAggron is a mono-steel pokemon with incredible defense and Filter, used when an opponent Physical Attacker is out may be the right moment to increase his speed. It may be something like this...

Pretty excited to try out this behemoth. Filter and steel typing really make this set, 4x weaknesses really debilitated aggron before, now it doesnt even have an 2x weaknesses.

On the topic of heavy slam, vs iron head. Heavy slam has 120 power if your opponent is 20% your weight or less, 100 power if your opponent is between 20% and 25%, 80 power if between 25% and 33%. After that, heavy slam is inferior to iron head. Iron head at 80 power is superior, especially if youre running thunderwave to get that paraflinch action going, but if key mons are nailed with a stronger heavy slam, it's probably worth it.

Mega Aggron weighs in at a rock solid 295kg, a bit heavier than regular aggron. So anything greater than 98kg is going to hit with a weaker attack than iron head. If a large number of mons in the OU tier, or where ever aggron ends up are heavier than 98kg, heavy slam isnt going to be worth it.

GOing over the tier of OU currently the number of mons hit by heavy slam harder than, or as hard as iron head is 32. 18 mons are hit weaker than heavy slam. This is generally favourable, nad with a more in depth analysis could mean that heavy slam would indeed be better. For example, a number of pokemon that heavy slam musters pathetic damage against such as magnezone, heatran, forretress, scizor and ferrothorn arent really an issue, because iron head is also going to do shit all against these pokemon and aggron generally has better things to do to those mons. Secondly a number of exceedingly light pokemon get nailed by a 120 or 100 power heavy slam, such as latias, keldeo, latios, reuniclus, blissey, celebi and a fair number of others. However, there are definitely a couple of issues with heavy slam. Dragonite, cloyster, salamence, and hydreigon all take 60 or 40 power from heavy slam, when iron head is aggron's beast STAB against these mons. One could argue that aggron is generally better off dragon tailing, or roaring these mons out, as they are hit super effectively by dragon tail, and/or are generally set up sweepers. HOwever, despite these arguments that could be made in heavy slam's favour 3 glaring and brutal weaknesses exist for heavy slam. Mamoswine, kyurem-b and terrakion, all pokemon that aggron can comfortably tank a hit from get nailed by iron head, however these same three mons are all hit by a 40 base power heavy slam. This coincidence of steel weak physical attackers that mega aggron can definitely check, or even come close to walling in kyurem-b's case also being the heaviest pokemon in the tier is simply unacceptable. So, sadly despite a lot of numbers and theory being in heavy slam's favour, to be honest, iron head is necessary for those specific three pokemon.

Pretty excited to try out this behemoth. Filter and steel typing really make this set, 4x weaknesses really debilitated aggron before, now it doesnt even have an 2x weaknesses.

Click to expand...

Unless I'm reading it incorrectly, Filter reduces the damage BY 25%, not TO 25%-- ie. a 4x super effective attack now down only 3x-- which will still destroy this poke. Well, it can survive a Terrakion Close Combat now anyway...

Terrakion is definitely not something aggron is going to counter, but can still check. Aggron's iron head is going to leave a real mark on terrakion when it comes down the wire. I think this just improve's mega aggron's viability to be honest. He's a steel type that brings all those resistances to the table, and a number of utilities, but a the same time still has the ability to check terrakion. Not many steel types can too boast this.

It's still very telling to see that Mega Aggron can almost take a +2 Life Orb Boosted 120BP super-effective move from one of the most terrifying sweepers of Gen V's meta.
I think he's going to work very well.

Aggron that run Brave natures. Shuckle leads hoping to Sticky Web. Slowbro hoping to get an early CM swe- oh, I just can't do this. Aggron has no chance of actually getting a Taunt off in the time where it matters.

Click to expand...

Yeah, I know Aggron is too slow to make good use of taunt, but it has it, so I figured I'd list it.

I'll be editing the OP with some of these sets and ideas, in addition to adding a more physically defensive set.

Rock Polish Mega Aggron might end up being a boss sweeper in standard / UU / etc. Once you set it up, your opponent is going to have a hard time revenge killing this thing. Filter makes it difficult to OHKO, and it shrugs off priority moves like a champ, so the only way to take it down is via certain Choice Scarf users. That mediocre Speed means that it's outsped by every scarfer though, and it's not particularly strong without a boosting item. It seems pretty good though.

If you're familiar with BW UU then you'd realize that this variant of Mega Aggron is basically a super Tank Rhyperior. You come in, wall stuff, set up SR, Attack or Dragon Tail and go along with your merry way. This set has 2 distinct flaws though; Mega Aggron can't actually switch into things until it Mega Evolves, so using it as a dedicated wall may put you at a disadvantage. It also lacks Leftovers, so it can rack up damage pretty quickly.

Mega Aggron is definitely a very interesting Pokemon and one of the few not all-out defensive MEvos we got. Steel-type with Filter and incredible physical bulk? Hell yeah! It's a shame that it faces such stiff competition with Landorus-T in OU and Rhyperior in UU, both of which have the advantage of better STAB(s), Leftovers, U-turn (in Lando-T's case), and better resistances to tank physical hits (Ground and Fighting for Landorus-T, Fire and Electric for Rhyperior, though the Electric resistance helps more with special attacks). Mega Aggron really needed a secondary typing, such as Poison (to actually wall physical Fighting Pokemon), Flying (to actually wall Ground Pokemon AND Fighting Pokemon), or Fairy (to wall Fighting Pokemon, and check Ghost and Dark-type Pokemon). Currently, he has only one mediocre STAB, low special bulk, and is susceptible to most of the top-tier physical attackers of OU (Terrakion, Landorus-T, Garchomp, Lucario, Breloom). Yeah it may avoid the OHKO from most of them even after a boost, but this alone means nothing, as in a Pokemon game residual damage and damage from resisted attacks happen, and they all take their toll very fast when you don't have Leftovers.

tl;dr very niche physical tank that can handle certain Pokemon better than its competitors (Lando-T and Rhyperior), such as Kyurem-B, Gyarados, and Choice Band Tyranitar (in Lando-T's case), but overall Landorus-T and maybe even Rhyperior will be the superior choices for physical tanks, having a much wider array of utility on a team.

I think you should add Ice Punch to the list of Notable Moves. With a move like Ice Punch Aggron can hit pokemon like Garchomp, Haxorus, Landorus-T, Salamance, Donphan and Hippowdon for super efective damage.

The extreme difference in roles between Aggron and Mega Aggron is even higher than Gengar and Mega Gengar. It switches from "Recoil what?" (No matter how, it will miss that STAB, recoil-less Head Smash) to "Skarmory who?" (Trading Ground and Fighting weaknesses to a physical defense Skarmory would die for. Then there's that 140 base Attack that stops Mega Aggron from being setup bait). Plus Aggron with Aggronite can still Head Smash with Rock Head, even if it does not hit as hard as with another item... but it can even bluff a Choice Band with its sheer power!

Mega Aggron can't actually switch into things until it Mega Evolves, so using it as a dedicated wall may put you at a disadvantage.

Click to expand...

not completely true, steel/rock sucks, but with mega evolution's priority and aggrons solid default defenses all you have to do is find one move to come in on. I mean, lets take a pokemon like staraptor for example. CLose combat tears aggron to shreds, but brave bird does about three damage. Aggron can find himself switching in on a move that isnt close combat, and then, mega evolving to comfortably take the close combat when it needs to. In fact it even plays in aggron's favour because he can take advantage of a couple of his 4x resistances, and then possibly even bait the opponent into thinking theyre about to hit a 4x weakness when theyre hitting a mere 1.5x weakness.

Imo aggron's biggest enemy is aggronite. Rhyperior in UU is a great pokemon, but leftovers help it A LOT.

It's probably a waste of a moveslot, but I'd like to try out a set with the new learned-by-everything TM Confide, which lowers SAtk by one stage. If used on a stall team with reliable Wish support (well it's not exactly hard for Meggron to switch in and take the Wish) and a bunch of hazards, it could become pretty much impenetrable from both the physical side and the special side and force the opponent to switch just to be able to deal ample damage to it.

This is all just theorymon (probably not even that; more like wishful thinking), but I'll be sure to try it when Gen 5.5 finally becomes Gen 6.

It's surprising how well it works considering how slow Aggron is. Thunder Wave paralyzes opponents and Iron Head will slowly paraflinch them to death. Earthquake is for dealing with Electric types. Mega Aggron is one of those mega evos that are much better than the base. It gets much better defenses and gets rid of the Rock type liability. The only problem it has is that it lacks recovery, so Wish passers or Heal Bell users are very much appreciated.

First turn I use Thunder Wave just about every turn. If it's a physical damage dealer or something I feel Aggron can deal with without much trouble, I'll handle it with a Steel STAB attack/Earthquake. If it's a special attacker, or something I don't really feel like fighting with Aggron, I just Dragon Tail it away. If Aggron gets Burned, I just swap over to Thunder Wave -> Dragon Tail and get their whole team paralyzed.

Or you can use Stealth Rock is amplify Dragon Tail's damage by quite a bit.

From there, I clean up with another slow, but heavy hitting, Pokemon, currently a Rotom-W using Hex/Hydro Pump/Volt Switch, but there's probably better chioces. I prefer Ghost types using Hex because 130 STAB move with very few resistances is really nice. Basically guaranteed going first without having to invest in speed on your sweeper is really nice.

It's surprising how well it works considering how slow Aggron is. Thunder Wave paralyzes opponents and Iron Head will slowly paraflinch them to death. Earthquake is for dealing with Electric types. Mega Aggron is one of those mega evos that are much better than the base. It gets much better defenses and gets rid of the Rock type liability. The only problem it has is that it lacks recovery, so Wish passers or Heal Bell users are very much appreciated.

Click to expand...

This is almost the exact Aggron I'm planning on trying out. The only difference is with mine, I'm planning him more offensive with an Adamant nature, 252 atk, and still undecided on the remaining EVs.

I know Mega Aggron already gets beastly defense, but how does it compare to something like a Mega Mawile smacking against it with no investment of any kind into defense and/or hp? I ask since I'm thinking of putting the other 252 just into Sp. Def., but can't help but think maybe a 3 way split of 84 EVs into hp, def, and sp. def. Or even 124 into hp/sp. def. if it's proven there really isn't any need to invest even a little into defense would be better. I'd do the calcs myself, but have no idea how. :(

Unless I'm reading it incorrectly, Filter reduces the damage BY 25%, not TO 25%-- ie. a 4x super effective attack now down only 3x-- which will still destroy this poke. Well, it can survive a Terrakion Close Combat now anyway...